admin For the first time, a team of scientists at the University of Bristol and the Technical University of Denmark has achieved quantum teleportation between two computer chips. The team managed to send information instantly from one chip to another without them being physically or electronically connected opening the door for quantum computers and quantum internet.
This kind of teleportation is made possible by a phenomenon called quantum entanglement, where two particles become so entwined with each other that they can “communicate” over long distances. Changing the properties of one particle will cause the other to instantly change too, no matter how much space separates the two of them. In essence, information is being teleported between them.
Hypothetically, there’s no limit to the distance over which quantum teleportation can operate – and that raises some strange implications that puzzled even Einstein himself. Our current understanding of physics says that nothing can travel faster than the speed of light, and yet, with quantum teleportation, information appears to break that speed limit. Einstein dubbed it “spooky action at a distance.”
Harnessing this phenomenon could clearly be beneficial, and the new study helps bring that closer to reality. The team generated pairs of entangled photons on the chips, and then made a quantum measurement of one. This observation changes the state of the photon, and those changes are then instantly applied to the partner photon in the other chip.
“We were able to demonstrate a high-quality entanglement link across two chips in the lab, where photons on either chip share a single quantum state,” says Dan Llewellyn, co-author of the study. “Each chip was then fully programmed to perform a range of demonstrations which utilize the entanglement. The flagship demonstration was a two-chip teleportation experiment, whereby the individual quantum state of a particle is transmitted across the two chips after a quantum measurement is performed. This measurement utilizes the strange behavior of quantum physics, which simultaneously collapses the entanglement link and transfers the particle state to another particle already on the receiver chip.”
The team reported a teleportation success rate of 91 percent, and managed to perform some other functions that will be important for quantum computing. That includes entanglement swapping (where states can be passed between particles that have never directly interacted via a mediator), and entangling as many as four photons together.
Information has been teleported over much longer distances before – first across a room, then 25 km (15.5 mi), then 100 km (62 mi), and eventually over 1,200 km (746 mi) via satellite. It’s also been done between different parts of a single computer chip before, but teleporting between two different chips is a major breakthrough for quantum computing.
As 2019 winds to a close, the journey towards fully realised quantum computing continues: physicists have been able to demonstrate quantum teleportation between two computer chips for the first time.
Put simply, this breakthrough means that information was passed between the chips not by physical electronic connections, but through quantum entanglement – by linking two particles across a gap using the principles of quantum physics.
We don’t yet understand everything about quantum entanglement (it’s the same phenomenon Albert Einstein famously called “spooky action”), but being able to use it to send information between computer chips is significant, even if so far we’re confined to a tightly controlled lab environment.
“We were able to demonstrate a high-quality entanglement link across two chips in the lab, where photons on either chip share a single quantum state,” explains quantum physicist Dan Llewellyn from the University of Bristol in the UK.
“Each chip was then fully programmed to perform a range of demonstrations which utilise the entanglement.”
Hypothetically, quantum entanglement can work over any distance. Two particles get inextricably linked together, which means looking at one tells us something about the other, wherever it is (in this case, on a separate computer chip).
To achieve their result, the team generated pairs of entangled photons, encoding quantum information in a way that ensured low levels of interference and high levels of accuracy. Up to four qubits – the quantum equivalent of classical computing bits – were linked together.
“The flagship demonstration was a two-chip teleportation experiment, whereby the individual quantum state of a particle is transmitted across the two chips after a quantum measurement is performed,” says Llewellyn.
“This measurement utilises the strange behaviour of quantum physics, which simultaneously collapses the entanglement link and transfers the particle state to another particle already on the receiver chip.”
The researchers were then able to run experiments in which the fidelity reached 91 percent – as in, almost all the information was accurately transmitted and logged.
Scientists are learning more and more about how quantum entanglement works, but for now it’s very hard to control. It’s not something you can install inside a laptop: you need a lot of bulky, expensive scientific equipment to get it working.
But the hope is that advances in the lab, such as this one, might one day lead to advances in computing that everyone can take advantage of – super-powerful processing power and a next-level internet with built-in hacking protections.
The low data loss and high stability of the teleportation, as well as the high level of control that the scientists were able to get over their experiments, are all promising signs in terms of follow-up research.
It’s also a useful study for efforts to get quantum physics working with the silicon chip (Si-chip) tech used in today’s computers, and the complementary metal-oxide-semiconductor (CMOS) techniques used to make those chips.
“In the future, a single Si-chip integration of quantum photonic devices and classical electronic controls will open the door for fully chip-based CMOS-compatible quantum communication and information processing networks,” says quantum physicist Jianwei Wang, from Peking University in China.
Source:atlas.com
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